ModBus connector?

[MarkRS]

I'm just wiring in an Elfin EW11 to my H1-5 inverter..

Although difficult I've managed to open up the connector and, contrary to the picture shown in Nathan Marlor's (excellent) guide the existing wire has only one connection, to pin 7.

There's another wire in there but it's not connected to anything!

Should it be connected into pin 8 according to Nathan's picture? It's quite possible I disconnected it (although I didn't see it happen).

In fact it looks like they've used an ethernet cable because the connected wire is actually a twisted pair (blue and white, both apparently in the connection) and the free-flying one is brown and white, although only the brown has exposed copper cable. I s'pose they might have only tightened the screw on the white and it got pulled out...

[Dave Foster]

Yes the CT clamp should be wired into 7 & 8 - these are small multi core cables and if you tighten the screw too much it breaks the cores, even a gentle breeze snaps them.

Wire it back into pin 8 and go careful with it

[MarkRS]

Thanks Dave! Will do

[MarkRS]

Having switched back on the figures (still from the Fox website) seem wrong.

Load power is showing as around 10W shy of PV Power, currently nearly 3kW and I don't think anything like that is actually being consumed, and Feedin Power is showing as zero, although the batteries are at 100%.

Does that make something I've done wrong obvious... or, errr.... not?

[Dave Foster]

Yes sounds like a CT problem, before looking at the wiring check the CT clamp is still enabled - on the inverter menu look in Settings, Feature, Meter/CT click set and it should say ‘CT’ if it doesn’t use the arrows to change it and set it (the inverter will restart).

If it is showing as CT enabled, it’s likely one of the CT cores isn’t connected properly - you mentioned lots of ‘spare’ colours so it would be worth finding the other end of that multi-core which will likely be where the CT clamp is at the smart meter - find which colours are being used then check that those colours are connected to pins 7&8.

[MarkRS]

Was still enabled. I'll have a look at the wiring, I expect I've jolted it. It's a very hard connector to open up to have such flimsy wires inside it. I re-purposed regular 13amp cable for the connection between it and the Elfin.

It's a nuisance as it stands, but is it a problem? Just wondering if it's a disaster if I leave it until the morning.

[Dave Foster]

It won’t be able to balance the load so the battery won’t be used and it’ll be on grid only once the sun goes down.

[MarkRS]

Hmm, ok, not just a nuisance then. I'll get on it

[MarkRS]

Ok, the wire is firmly connected but I'm still not seeing feed-in or grid consumption power.

The wire I've "firmly connected" is the one of the twisted pair that still has copper showing. Would it be sensible to assume that they only connected the other one of that pair at the other end, or should I look for something else wrong?

I'm nervous because I'm not sure how I'm going to strip back the other wire if it's so fragile, I don't have a pair of wire strippers any more .

[Dave Foster]

You need to find the other end of the cable where the CT clamp is (near the smart meter) and establish which colours they have used in the multi-core cable. Once you know what colours are used it will make the job much easier as at least you’ll know which core to strip otherwise it’s a lottery.

But just a thought before you do that, have you shut down and restarted the inverter since you have re-connected the cable

[MarkRS]

I shut down the inverter to fiddle with the connector and then restarted it. I've also reset the ctclamp setting on the menu that you spoke about too, not that it had become disabled.

[MarkRS]

I've just had a look at the CT clamp and found this (see pictures).
Really poor pictures, really hard to get any kind of good picture.
Doesn't help much, I think.

[Dave Foster]

I'm not sure that tells us much, the standard CT clamp is a white clamp with the words 'Split Core CT' and 'CTSA016-100A' written on the top - it has a black sheathed cable that comes out of it but the cores inside are black and white and I can't see that in those photo's - that might mean they have used a different CT clamp or put a RED sheaf around the white cable.

But going back to your original post you thought they had used 2 twisted pairs a blue and white and a brown and white (if it is a cat5 cable the whites would actually be white/blue and white/brown stripes) - we can see that the brown/white and blue/white cables have been left cut which suggests it is the brown and the blue cores that are carrying the CT signal.

Without a better picture and reading back through what you said I would suggest the cores that should be connected in the meter connector are BLUE to Pin 7 and BROWN to PIN 8

Note at the CT end the RED core looks like it might be loose in the connector so worth double checking that hasn't been pulled loose.

[MarkRS]

Strange that, at the inverter, the blue and white and the blue should both be wired into the connector if they only connect one of them at the other end?
I assume both the brown and white and the brown where both wired in, but those were the free-flying ones when I opened it up.

Any road up, I think you're right. I acquired a pair of wire strippers and managed to strip and then connect the brown (as well as the brown and white) and now it is working!

Not only that, but the Elfin is working too and I'm getting data direct!

Thanks for your help (again again again!)